The farm is quiet but constantly moving, as the faint sound of bleats in the distance breaks the silence.

Prairie Fruits Farm & Creamery in Champaign was making cheese from its herd of 75 milking goats on a recent afternoon just like any other, but this time for a very different customer. The 13-year-old organic farm is the primary regional supplier of goat cheese for salad chain Sweetgreen, which opens its first Chicago location Tuesday.

Sweetgreen has 11 locations in Washington, D.C, where it got its start, 33 other stores along the East Coast and five in California. For its first store in the Midwest the salad chain, which is committed to locally grown foods and sustainable farming, had to develop a new farm supply and distribution system from scratch.

It's a rare path in the restaurant industry and virtually unheard of in fast food, but the method has become status quo for Sweetgreen. Founded in 2007 by three Georgetown University students, Sweetgreen bases its menu on seasonal produce that varies depending on location. The menu changes five times a year and features salad and grain bowls with house-made dressings that range from about $9 to $12. Beverages also are made daily in-store.

"Early on, we believed that ... we wanted to change this model of fast food, not just in terms of being healthy and accessible but really defining what that meant," co-founder Nicolas Jammet said. "And for us, our food ethos was about honoring the land and understanding that people should have closer connections to their food and this idea that transparency is everything. So not only being able to source incredible ingredients, but wanting our customers to know where they came from and connecting with it."

[Our] food ethos was about honoring the land and understanding that people should have closer connections to their food and this idea that transparency is everything.— Nicolas Jammet, Sweetgreen co-founder

The company started looking at Chicago suppliers about a year ago.

Sourcing local and sustainable produce and meats comes with big risks that have challenged far bigger competitors. Chipotle stopped selling pork carnitas in many of its restaurants last year after it dropped a supplier that violated its standards. And big food distributors aren't always willing to pick up from certain farms, especially smaller ones.

Prairie Fruits Farm, owned and operated by Leslie Cooperband and her husband Wes Jarrell, will initially send 100 pounds of goat cheese per week to the Sweetgreen restaurant in River North, by very untraditional means: Amtrak. The goat cheese will be travel by rail from Champaign to Union Station in Chicago, where it will be trucked on its final leg to the store. That haul will double to 200 pounds next spring.

Cooperband admits she was nervous at first that the farm would not be able to meet Sweetgreen's hefty demand for goat cheese, but said that she was grateful they were able to partner for a smaller load initially.

That flexibility is important, Sweetgreen's founders say, because they don't want small farmers excluded for being unable to immediately meet their high volume requirements.

Sweetgreen says it also wants to be flexible with some ingredients to adjust to what farmers do best. It is serving cremini mushrooms for the first time on its Chicago menu because they are the primary crop at chosen supplier River Valley Ranch in Burlington, Wis.

River Valley Ranch owner Eric Rose said the order will be "a couple hundred pounds" to start and then adjust depending on demand. Rose — who supplies Chicago restaurants like Frontera and Antique Taco in addition to his own restaurant in Ravenswood, River Valley Farmer's Table — called Sweetgreen's attention to food and sourcing "pretty rare."

Phil Velasquez / Chicago Tribune

Goats make their way to pasture Aug. 17, 2016, to graze at Prairie Fruits Farm & Creamery in Champaign.

Goats make their way to pasture Aug. 17, 2016, to graze at Prairie Fruits Farm & Creamery in Champaign.

(Phil Velasquez / Chicago Tribune)

"They took such an active interest in their food and we're proud to be part of the process," he said.

Sweetgreen found Prairie Fruits through FamilyFarmed, a nonprofit organization that aims to increase local and organic food sales. It cemented some other deals with farmers, including River Valley Ranch, through the Green City Market. It will get kale from Growing Power, from farms in Milwaukee. Tofu will come from Edgewater's Phoenix Bean and bread from Hewn Bakery in Evanston. Produce suppliers are farms across Illinois, Wisconsin, Indiana and Michigan, and are generally less than two hours away. Ingredients traveling the longest distances will be chicken from Tecumseh Farms in Nebraska, wild shrimp from the Gulf of Mexico and Steelhead trout from Washington state.

Co-founder Nathaniel Ru said when Sweetgreen runs out of a certain menu item due to factors like weather or seasonality, the missing ingredients will be listed under a tongue-in-cheek banner, "Mama said there'll be days like this."

They took such an active interest in their food and we're proud to be part of the process.— River Valley Ranch owner Eric Rose

Sweetgreen plans to set down roots in Chicago over the next few years, adding a second store next year at 1000 W. Randolph St. in the neighborhood known as West Loop, Fulton Market or West Town, and a "few more" in Chicago in the near future, co-founder Jonathan Neman said. The company then plans to use Chicago as the hub that allows it to expand to the rest of the Midwest.

"We believe where you go, when you go, how fast you go says a lot about you, and so for us, it's slow, steady, conscious intentional growth," he said.

Providing year-round local produce from the Midwest may be the most difficult challenge yet for the company because of the region's often unpredictable climate and harsh winters. There are some menu items that can't be grown locally, like avocados, which are brought in from more temperate climates like California and stay on the menu because of customer demand. And kale, the widest-used ingredient on the menu, will be grown in the Midwest in the warmer months but will be brought in from elsewhere when it's too cold.

"Even though we wanted to create this consistent experience in terms of quality and standards, the promise was not consistency and standardization." Jammet said. "So the idea that food tastes different in different parts of the country at different points of the year, is kind of the promise. The kale that grows in New Jersey in September is going to taste different than the kale that comes out of the ground in California. And that's OK. That's actually what we want to celebrate."